We propose a two-group randomized trial of Project Prepared, an HIV/STI prevention program for youth aged 12-14. It folds together elements of three interventions we designed for middle adolescents into a comprehensive intervention that is developmentally appropriate for youth in early adolescence. Project Prepared has two parts. First is a 14-session training program held over 7 weeks that covers five major predictors of high risk behavior: developmental navet, cognitive factors, gender roles, relationship factors and family formation. It is followed by a 5-week internship that incorporates resilience and youth development through making youth peer educators to other adolescents about HIV/STI risk. Project Prepared is theoretically based, comprehensive, intensive, and appropriate to the developmental stage, race/ethnicity, and social context of inner-city youth of color. It emphasizes skills in avoiding risky sexual situations, and provides medically accurate information about sexual development, sexually transmitted infections and pregnancy. We will conduct a two group randomized trial (n=400) to test the effectiveness of Project Prepared on cognitive factors (HIV/STI knowledge, sexual self-efficacy; intention to use a condom); relationship factors (immature romantic beliefs, relationship self-efficacy), gender norms (macho man, powerless female), and resilience. The control condition will be TEEN, an award winning program with proven effectiveness in reducing psychological symptoms with no HV/STD content.